The present invention relates to a pattern recognition apparatus and, more particularly, to a pattern recognition apparatus capable of providing a contouring line data of image data large enough to extend over each of partitioned regions by partitioning image data into the partitioned regions and connecting each of the partitioned regions by implementing connection processing of the image data between the partitioned regions.
Heretofore, image processing apparatuses, such as computer-aided design devices (CAD) and so on, involve extracting various shapes from a line drawing containing various line segments and classifying them into line drawing elements in processing drawing data by digitizing the line drawing. As a pre-processing for classification processing or for processing pattern recognition of a drawing, there is implemented an extraction processing for extracting the contouring line data from the image data.
For such image processing apparatuses, such as CAD and the like, line drawing as an object to be processed becomes larger as technology advances in recent years so that increasing demands have been made to provide a device capable of processing drawing data of a large size. However, the image processing apparatuses have a limited memory capacity of image memory in the processing unit so that a size of the drawing capable of being read at once by the image memory and processed is limited, too. Thus, pending U.S. patent application Ser. No. 272,826, filed Nov. 18, 1988, now U.S. Pat. No. 5,134,572, to the present inventors proposes an image processing system for an image processing device such that a large image data is partitioned into partitioned regions and image processing is implemented in each of the partitioned regions, followed by the connection processing of each of the partitioned image data, thus implementing the image processing of the large image data. The partitioned image processing system proposed in the pending U.S. patent application involves image processing of the large image data partitioned.
This system permits processing a large image data by partitioning the large image data into partitioned regions and then connecting each of the partitioned regions. If this system is applied to a pattern recognition apparatus providing a contouring line data, however, a contouring line data in the large image data, when processed by partitioning into partitioned regions, becomes an open drawing in each of the regions. Accordingly, conventional technique of extracting contouring line data cannot be applied to such partitioned regions. Extraction of the contouring line data in the large image data should thus be subjected to image processing using an image memory having a large memory capacity in which image data is once stored in the image memory.
Such a conventional pattern recognition apparatus is so designed, as disclosed in Japanese Patent Publication (laid-open) No. 117,381/1985, that once image data is produced, all image data are stored in an image memory and a contouring line data is given at once.
However, conventional technique should store the given image data in an image memory at once so that it requires a large image memory in order to produce a contouring line data from a large amount of the image data.